Interlocking finned heat exchange envelope



Dec. 21, 1954 A. JENSEN INTERLOCKING FINNED HEAT EXCHANGE ENVELOPE FiledAug. 4. 1950 on 00000 cocoon 0000c ri/wr dense/5 BY l 2 w 8 An S a a M 0a 3 0/ 4 n l w p. m m H. w a m u p p. m P, (I y L .4 Jr 11 i r l UnitedStates Patent WTERLOCKING FINNED HEAT EXCHANGE ENVELOPE Arthur Jensen,Wellsville, N. Y., assignor to The Air Preheater Corporation, New York,N. Y.

Application August 4, 1950, Serial No. 17 7,579

9 Claims. (Cl. 257-245) The present invention relates to improvements inplate type heat exchange apparatus and particularly to those in whichone of the fluids flows through the exchanger under high pressure.

A well known form of heat exchange apparatus for the transfer of heatbetween two confined fluids is made up of a plurality of spaced metallicplates forming passages through alternate ones of which a heating fluid,such as a hot gas, flows in heat exchange relationship with the fluid tobe heated, such as air, traversing the intermediate passages. In manysuch exchangers a series of envelopes are provided consisting ofparallel plates with the space therebetween closed along one pair ofopposite edges to bound the sides of the passage for one of the fluidssuch as air to be heated. The envelopes are mounted in spaced parallelrelation to form the passages for the other fluid or heating gas and theinter-envelope spaces are likewise closed along one pair of .oppositeside edges of the envelopes, which sides may be those extending parallelto the closed edges of the air envelopes in case of parallel flow, oralong the adjacent sides in case of transverse flow. Such spacedenvelopes form a core that is usually enclosed within a housing which,when one of the fluids is under high pressure, involves the employmentof an expensive and heavy outside shell to withstand the pressure.

An object of the present invention is to construct a heat exchanger ofthe type mentioned above by forming and joining the envelopes togetherin such a way that they strengthen and support each other and so as torender it unnecessary to also utilize a heavy and expensive housing.

The invention will best be understood upon consideration of thefollowing detailed description of illustrative embodiments thereof whenread in conjunction with the accompanying drawings in which:

Figure 1 is a diagrammatic view in longitudinal section of a plate typeheat exchanger embodying the present invention and illustrates themanner of forming the air envelopes and rigidly connecting them togetherto create a heat exchanger.

Figure 2 is a fragmentary sectional view along the line 22 in Figure 1showing part of the heat exchanger.

Figure 3 is a sectional view on the line 3-3 in Figure 2; and

Figures 4, 5 and 6 are fragmentary views similar to Figure 2 showingalternative constructions for forming and joining the parallel envelopesinto a heat exchanger.

Referring first to Figure 1, a fluid under low pressure, such as hotgas, is admitted to the heat exchanger, designated as a whole by thenumeral 10, through an inlet connection 11 and distributed by themanifold 12 to a series of gas passages 13 (Fig. 2) disposed inalternation with the passages 14 through which is circulated a fluidunder high pressure, such a air to be heated. Header plates 15 and 16 inthe inlet manifold 12 and the outlet manifold 17 have parallel slotsleading to the gas passages and intermediate imperforate portions thatclose the end of the air passages 14 so that the heating gas in flowinglongitudinally of the exchanger is confined to the gas passages 13before it is discharged from the manifold 17 through the outletconnection 18. The other fluid, which may be air under high pressure,enters the heat exchanger 10 through the side inlet connection 20 and isdirected into the air passages 14 by guide vanes 21 and is dischargedthrough an outlet connection 23,

2,697,588 Patented Dec. 21, 1954 the air'entering and leaving the airpassages 13 at locations adjacent opposite ends of the exchanger throughthe sides of the passages at these points. The foregoing generalconstruction is conventional.

As mentioned above the heat exchanger is made up of a plurality ofenvelopes designated as a Whole in Figure 2 by the numeral 30. Each ofthese envelopes comprises a pair of parallel metallic plates 32 and 33spaced to form an air passage 14, the envelopes being mounted in spacedrelation to form therebetween the gas passages 13. Metal bars or strips34 mounted between the plates 32 and 33 are welded thereto along theirside edges to close the sides of the air passages. Near the ends of theexchanger parts of these metallic strips are omitted at the bottom ofeach envelope opposite the air inlet 20 and at the top of the envelopesopposite the air outlet 23 so that air may be admitted to and taken fromthe envelopes which define the air passages 14 alternating with the gaspas-' sages 13.

To improve the transfer of heat from the hot gas flowing in the passages13 through the walls 32, 33 to the air flowing in the passages 14 thewalls are provided with extended surfaces in the form of pin fins 35bonded in good heat transfer relationship to the surfaces of the plates32 and 33 that confront the air passage 14 within an envelope 30. Asdisclosed in greater detail in the copending application of Peter Hodsonand Sven 'Holrn Serial No. 152,952 filed March 30, 1950 the pin 'fins 35are parts of metallic wires bent sinusoidally to form a seriesofsubstantially U-shaped loops whose leg portions 36 (Fig. 3) constitutethe pin fins while the intermediate yokes or stretcher portions 37 areengaged in mounting channels 38, the wires being brazed to the channels38 and the latter to the surfaces of the plates 32 and 33 bounding theair passages within the envelopes.

On the gas side the plates 32, 33 forming the envelopes 30 are providedwith a plurality of parallelly spaced, longitudinally extending channelmembers 40, 41 which constitute extended surfaces of these walls intothe gas passages for improving the efliciency of the heat transfer fromthe gas to the walls 32, 33 and through the latter to the air on theopposite sides thereof. To maintain the envelopes in desired spacedrelationship and to tie them rigidly together the legs 42 of the spacedchannel members 40, 41 are provided along their longitudinal edges withlaterally extending flanges or lips 43 that engage and interlock withthe similar flanges on the channels of the adjacent envelopes. Theenvelopes assembled in the relationship described may be formed into anintegral monolithic core by brazing the interlocked lips 43 of thechannels together to provide for the interlocking relationship. Itshould be noted that the lips 43 on the velopes extend in the oppositedirection, as downwardly, so that when several envelopes arejuxtapositioned the lips 43 on the two sets of channels interlock witheach other. Nevertheless, all of these channels may be formed in thesame manner so that they are duplicates, the reversed relationship beingproduced simply by turning the channels on one side of an envelope endfor end with respect to those on the other side of the envelope so thattheir lips extend in opposite directions, as upwardly in one case anddownwardly in the other. The spaces between adjacent envelopes areclosed along their upper and lower longitudinal side edges by the narrowmetallic strips 44. These strips in addition to joining the envelopestogether along their longitudinal side edges form the longitudinalclosure members for the sides of the gas passages 13 between theenvelopes which alternate with the air passages 14 within the envelopes.Together with the strips 34 that close the corresponding sides of theenvelopes the strips 44 constitute the top and bottom walls of the heatexchanger. Plates 47 forming closuresfor the sides of the heat exchangerare joined along their upper and lower longitudinal edges to theoutermost longitudinal strips 46 at the sides of the assembledenvelopes, the exchanger thus requires no separate shell to enclose it.To this heat exchanger consisting of a series of rigidly assembled,spaced envelopes the inlet and outlet manifolds 12, 17 for the twofluids may be connected in any suitable manner this not being a specialfeature of the present invention.

In Figure 4 the channel members which are designated 50 are providedwith generally T-shaped side legs 51 so that lateral flanges extend inboth directions from opposite longitudinal edges of the channel legs.The lateral flanges 52 are chamfered on their under sides thus producingan undercut slot facing the base of each channel so that a mortise ordovetailed interlocking arrangement is provided by the channels. Eachchannel on one plate interlocks with two on the other plate, thesechannels not being directly opposite but offset to either side.

In Figure the channel members 60 are also offset and have theirinterlocking lips formed by curling over the outer edges of the legportions to provide a hook-like interlocking arrangement consisting of are-entrant groove 61 along the edge of each channel leg 62 receiving thecurled-over longitudinal edge portion 63 of the associated channel onthe adjacent envelope.

In Figure 6 the means for connecting and spacing the adjacent envelopes30 are separate from other channel members 70. Here there are providedon the outer wall surface of the envelopes longitudinally extendingmembers 71 having flange portions 72 and 73 bent inwardly and downwardlytowards each other to form a groove, like the slot in Fig. 4, forreceiving the roughly T-shaped end 74 of a tie member 75 which insection resembles an I-beam. The members 71 also are to be considered aschannel form surface extending fins on the walls confronting the gaspassages.

Although the gas passages 13 have been shown as paralleling the airpassages 14 it will be understood that cross-flow of the fluids might beemployed, in which case the channels 40, 41 etc. would extendtransversely of the envelope plates rather than parallel with the wirefin elements.

What I claim is:

1. In a heat exchanger for two confined fluids including envelopecomponents each comprising parallelly spaced plates joined along onepair of opposite side edges to form within each envelope a passage forone fluid with the envelope components disposed contiguously in spacedparallel relation; heat transfer fin elements consisting of channelmembers bonded in spaced parallel relation to the outer wall surfaces ofeach pair of contiguous envelopes and projecting therefrom toward eachother and formed with laterally projecting lip portions interlockingwith channel lip portions of channels on contiguous envelopes so as tojoin the envelopes together; and closure means joining contiguousenvelopes along one pair of opposite side edges to form side walls forthe passages for said other fluid between the envelopes.

2. A heat exchanger as recited in claim 1 wherein the channel membersare of substantially U-shape with straight legs provided at their distalends with lateral flanges.

3. A heat exchanger as recited in claim 1 wherein the channel membersare of substantially U-shape with straight legs each provided withT-shaped distal ends chamfered on the underside of the T cross-bar.

4. A heat exchanger as recited in claim 1 wherein the channel membersare of substantially U-shape with straight legs provided at their distalends with lateral flanges extending at right angles.

5. A heat exchanger as recited in claim 1 wherein the channel membersare of substantially U-shape with straight legs provided at their distalends with lateral flanges extending at right angles in the samedirection from both legs.

6. A heat exchanger as recited in claim 1 wherein the channel membersare of substantially U-shape with straight legs each provided at itsdistal end with a lateral flange which extends in the same directionfrom both legs at right angles thereto.

7. A heat exchanger as recited in claim 1 wherein the sides of thechannel members are inclined toward each other to provide an undercutslot therebetween; and an I-beam member engaged in the slots of channelmembers on contiguous envelopes to interlock the latter.

8. A heat exchanger as recited in claim 1 wherein the distal ends of thechannel members are hook shaped.

9. In a heat exchanger provided with inlet and outlet connectionsleading to passages for two confined fluids arranged in alternation andincluding envelope components each comprising plates spaced parallellyto form within the envelopes the passages for one fluid with theenvelope components disposed contiguously in spaced parallel relation toform therebetween passages for the other fluid; heat transfer finelements consisting of channel members bonded to the outer wall surfacesof each pair of contiguous envelopes and projecting therefrom towardeach other with their distal ends formed with interlocking lateral lipportions so as to rigidly join the envelopes together; closure meansjoining the plates of each envelope along one pair of opposite sideedges; and closure means joining contiguous envelopes together alongsaid one pair of opposite side edges to form side walls for the passagesbetween the envelopes for said other fluid and acting to maintain saidchannel members interlocked by spreading said plates, both said closuremeans constituting parts of opposite walls forming the casing structureof the exchanger.

References Cited in the file of this patent UNITED STATES PATENTSFOREIGN PATENTS Country Date Great Britain Feb. 3, 1944 Number Number

